Visuoconstructional problems in dementia: contribution of executive systems functions

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurology

Background:

• Visuoconstructional deficits are common in neurodegenerative diseases.
• Differentiating cognitive profiles across Alzheimer's disease (AD), ischaemic vascular dementia (IVD), and Parkinson's disease (PD) is crucial for diagnosis and management.

Purpose of the Study:

• To assess and compare visuoconstructional abilities in patients with AD, IVD, and PD.
• To identify neuropsychological correlates of visuoconstructional performance in these dementia subtypes.

Main Methods:

• Participants diagnosed with AD, IVD, PD, and a normal control (NC) group copied a modified Rey-Osterrieth Complex Figure (M-ROCF).
• Neuropsychological tests assessing working memory and executive functions were administered.
• Correlational analyses examined relationships between M-ROCF performance and cognitive test scores.

Main Results:

• Normal controls outperformed all dementia groups.
• AD patients generally showed better M-ROCF performance than IVD and PD patients, who exhibited fragmented drawings with perseverations and omissions.
• Despite drawing errors, IVD and PD patients had higher delayed recognition memory scores than AD patients.
• Accurate M-ROCF copying strongly correlated with working memory performance, not with executive functions like response inhibition.

Conclusions:

• Visuoconstructional ability is impaired across AD, IVD, and PD, with varying severity.
• Working memory is a key cognitive domain supporting accurate visuoconstructional performance in dementia.
• Executive functions, particularly response selection/inhibition, do not appear to be primary drivers of visuoconstructional ability in these conditions.